Like I said earlier, FB is the devil ! I deleted mine after my first break up with the ex because even if I would have deleted him I would still see pictures of him on events through Mutual friends.
Anyways, I think that at the time you de-friended him he didn’t really think about the fact you did. Sometimes (and not wanting to generalize) men start to think about someting, or start to get bothered about something later on and take action.
The fact he removed tagged pictures isn’t even a bad sign, it shows some kind of anger whIch shows he still cares. Someone who doesn’t care wouldn’t be bothered, I have friends dating new girls who still have all the pictures of their ex on FB simply cause they don’t care. If they delete our stuff … and block us … They care !
My ex even blocked my mom when he saw she deleted him.